This application claims priority under 35 U.S.C. xc2xa7371 to WO 00/44874, filed Feb. 1, 1999.
The present invention relates to a cationic surfactant particle, particulate detergent compositions containing such cationic particle, and a process for making thereof.
Recently, there has been considerable interest within the detergent industry for laundry detergents which are xe2x80x9ccompactxe2x80x9d and therefore, have low dosage volumes. To facilitate production of these so-called low dosage detergents, many attempts have been made to produce high bulk density detergents, for example with a density of 600 g/l or higher. The low dosage detergents are currently in high demand as they conserve resources and can be sold in small packages which are more convenient for consumers. However, the extent to which modem detergent products need to be xe2x80x9ccompactxe2x80x9d in nature remains unsettled. In fact, many consumers, especially in developing countries, continue to prefer a higher dosage levels in their respective laundering operations. Consequently, there is a need in the art of producing modem detergent compositions for flexibility in the ultimate density of the final composition.
Currently, the relative amounts and types of materials subjected to processes in the production of detergent granules has been limited. For example, it has been difficult to attain high levels of surfactant in the resulting detergent composition, a feature which facilitates production of detergents in a more efficient manner. Cationic surfactants are a common surfactant as well as co-surfactant for use in detergent compositions and is commonly available in a liquid form. In general, detergent compositions will contain one or more types of surfactants which are designed to loosen and remove different types of soils and stains.
Based on the foregoing, there is a need for a cationic surfactant material which is in a form that is easily incorporated into particulate detergent compositions. None of the existing art provides all of the advantages and benefits of the present invention.
The present invention relates to a cationic particle containing an aqueous cationic surfactant solution adsorbed to a water-insoluble high absorbing material. A process for making the cationic particle is also described herein. These and other features, aspects, and advantages of the present invention will become evident to those skilled in the art from a reading of the present disclosure.
While this specification concludes with claims distinctly pointing out and particularly claiming that which is regarded as the invention, it is believed that the invention can be better understood through a careful reading of the following detailed description of the invention. In this specification, all percentages, ratios, and proportions are by weight, all temperatures are expressed in degrees Celsius, molecular weights are in weight average, and the decimal is represented by the point (.), unless otherwise indicated.
As used herein, xe2x80x9ccomprisingxe2x80x9d means that other steps and other ingredients which do not affect the end result can be added. This term encompasses the terms xe2x80x9cconsisting ofxe2x80x9d and xe2x80x9cconsisting essentially ofxe2x80x9d.
All cited references are incorporated herein by reference in their entireties. Citation of any reference is not an admission regarding any determination as to its availability as prior art to the claimed invention.
The present invention relates to a cationic particle containing an aqueous cationic surfactant solution adsorbed to a water-insoluble high absorbing material. It is beneficial to have the cationic surfactant in a particulate form for various reasons, since cationic surfactants are commonly available in liquid solution form. For example, in processing particulate detergent compositions in non-tower processes, the liquid cationic surfactant may make the mixture during agglomeration sticky due to the excess moisture. In addition, the cationic particle can be made a higher active particle, as compared to its liquid form, which provides formula space when formulating a particulate detergent composition. In addition, the cationic particle of the present invention has good dispersion and solubility when used in the wash water.
The present invention also meets the aforementioned needs in the art by providing a cationic particle which can be used to produce a particulate detergent composition for flexibility in the ultimate density of the final composition.
As used herein, the term xe2x80x9cmean residence timexe2x80x9d refers to following definition: xe2x80x9cmean residence time (hr)=mass (kg)/flow throughput (kg/hr)xe2x80x9d.
Cationic Surfactant Solution
The cationic particle of the present invention contains an aqueous cationic surfactant solution. The cationic surfactant solution has at least about 70% water, preferably from about 40% to about 60%, more preferably from about 50% to about 60%, by weight of the surfactant solution. The amount of cationic active in the aqueous cationic surfactant solution is at least about 30%, preferably from about 40% to 60%, more preferably from about 40% to 50%.
Preferably the cationic surfactant is selected from the group consisting of cationic ester surfactants, cationic mono-alkoxylated amine surfactants, cationic bis-alkoxylated amine surfactants and mixtures thereof. Preferred quaternary ammonium surfactants are selected from mono C1-C30, preferably C6-C16 N-alkyl or alkenyl ammonium surfactants wherein remaining N positions are substituted by methyl, hydroxyethyl or hydroxypropyl groups.
Useful cationic surfactants include water-soluble quaternary ammonium compounds of the form R4R5R6R7N+Xxe2x88x92, wherein R4 is alkyl having from 10 to 20, preferably from 12-18 carbon atoms, and R5, R6, and R7 are each C1 to C7 alkyl preferably methyl; Xxe2x88x92 is an anion, e.g. chloride. Examples of such trimethyl ammonium compounds include C12-14 alkyl trimethyl ammonium chloride and cocoalkyl trimethyl ammonium methosulfate.
Cationic surfactants also useful is a cationic choline ester-type quat surfactant which are preferably water dispersible compounds having surfactant properties and comprise at least one ester (i.e. xe2x80x94COOxe2x80x94) linkage and at least one cationically charged group. Suitable cationic ester surfactants, including choline ester surfactants, have for example been disclosed in U.S. Pat. Nos. 4,228,042, 4,239,660 and 4,260,529.
Preferred cationic ester surfactants are those having the formula: 
wherein R1 is a C5-C31 linear or branched alkyl, alkenyl or alkaryl chain or Mxe2x88x92.N+(R6R7R8)(CH2)s; X and Y, independently, are selected from the group consisting of COO, OCO, O, CO, OCOO, CONH, NHCO, OCONH and NHCOO wherein at least one of X or Y is a COO, OCO, OCOO, OCONH or NHCOO group; R2, R3, R4, R6, R7 and R8 are independently selected from the group consisting of alkyl, alkenyl, hydroxyalkyl, hydroxyalkenyl and alkaryl groups having from 1 to 4 carbon atoms; and R5 is independently H or a C1-C3 alkyl group; wherein the values of m, n, s and t independently lie in the range of from 0 to 8, the value of b lies in the range from 0 to 20, and the values of a, u and v independently are either 0 or 1 with the proviso that at least one of u or v must be 1; and wherein M is a counter anion.
Preferably R2, R3 and R4 are independently selected from CH3 and xe2x80x94CH2CH2OH.
Preferably M is selected from the group consisting of halide, methyl sulfate, sulfate, and nitrate, more preferably methyl sulfate, chloride, bromide or iodide.
Preferred water dispersible cationic ester surfactants are the choline esters having the formula: 
wherein R1 is a C11-C19 linear or branched alkyl chain.
Particularly preferred choline esters of this type include the stearoyl choline ester quatemary methylammonium halides (R1=C17 alkyl), palmitoyl choline ester quaternary methylammonium halides (R1=C15 alkyl), myristoyl choline ester quatemary methylammonium halides (R1=C13 alkyl), lauroyl choline ester quaternary methylammonium halides (R1=C11 alkyl), cocoyl choline ester quaternary methylammonium halides (R1=C11-C13 alkyl), tallowyl choline ester quatemary methylammonium halides (R1=C15-C17 alkyl), and any mixtures thereof.
The particularly preferred choline esters, given above, may be prepared by the direct esterification of a fatty acid of the desired chain length with dimethylaminoethanol, in the presence of an acid catalyst. The reaction product is then quatemized with a methyl halide, preferably in the presence of a solvent such as ethanol, propylene glycol or preferably a fatty alcohol ethoxylate such as C10-C18 fatty alcohol ethoxylate having a degree of ethoxylation of from 3 to 50 ethoxy groups per mole forming the desired cationic material. They may also be prepared by the direct esterification of a long chain fatty acid of the desired chain length together with 2-haloethanol, in the presence of an acid catalyst material. The reaction product is then quaternized with trimethylamine, forming the desired cationic material.
Other suitable cationic ester surfactants have the structural formulas below, wherein d may be from 0 to 20. 
In a preferred aspect these cationic ester surfactant are hydrolysable under the conditions of a laundry wash method.
Cationic surfactants useful herein also include alkoxylated quatemary ammonium (AQA) surfactant compounds (referred to hereinafter as xe2x80x9cAQA compoundsxe2x80x9d) having the formula: 
wherein R1 is a linear or branched alkyl or alkenyl moiety containing from about 8 to about 18 carbon atoms, preferably 10 to about 16 carbon atoms, most preferably from about 10 to about 14 carbon atoms; R2 is an alkyl group containing from one to three carbon atoms, preferably methyl; R3 and R4 can vary independently and are selected from hydrogen (preferred), methyl and ethyl; Xxe2x88x92 is an anion such as chloride, bromide, methylsulfate, sulfate, or the like, sufficient to provide electrical neutrality. A and Axe2x80x2 can vary independently and are each selected from C1-C4 alkoxy, especially ethoxy (i.e., xe2x80x94CH2CH2Oxe2x80x94), propoxy, butoxy and mixed ethoxy/propoxy; p is from 0 to about 30, preferably 1 to about 4 and q is from 0 to about 30, preferably 1 to about 4, and most preferably to about 4; preferably both p and q are 1. See also: EP 2,084, published May 30, 1979, by The Procter and Gamble Company, which describes cationic surfactants of this type which are also useful herein.
AQA compounds wherein the hydrocarbyl substituent R1 is C8-C11, especially C10, enhance the rate of dissolution of laundry granules, especially under cold water conditions, as compared with the higher chain length materials. Accordingly, the C8-C11 AQA surfactants may be preferred by some formulators. The levels of the AQA surfactants used to prepare finished laundry detergent compositions can range from about 0.1% to about 5%, typically from about 0.45% to about 2.5%, by weight.
According to the foregoing, the following are nonlimiting, specific illustrations of AQA surfactants used herein. It is to be understood that the degree of alkoxylation noted herein for the AQA surfactants is reported as an average, following common practice for conventional ethoxylated nonionic surfactants. This is because the ethoxylation reactions typically yield mixtures of materials with differing degrees of ethoxylation. Thus, it is not uncommon to report total EO values other than as whole numbers, e.g., xe2x80x9cEO2.5xe2x80x9d, xe2x80x9cEO3.5xe2x80x9d, and the like.
The preferred bis-ethoxylated cationic surfactants herein are available under the trade name ETHOQUAD from Akzo Nobel Chemicals Company.
Highly preferred bis-AQA compounds for use herein are of the formula 
wherein R1 is C10-C18 hydrocarbyl and mixtures thereof, preferably C10, C12, C14 alkyl and mixtures thereof, and X is any convenient anion to provide charge balance, preferably chloride. With reference to the general AQA structure noted above, since in a preferred compound R1 is derived from coconut (C12-C14 alkyl) fraction fatty acids, R2 is methyl and ApR3 and Axe2x80x2qR4 are each monoethoxy, this preferred type of compound is referred to herein as xe2x80x9cCocoMeEO2xe2x80x9d or xe2x80x9cAQA-1xe2x80x9d in the above list.
Other preferred AQA compounds herein include compounds of the formula: 
wherein R1 is C10-C18 hydrocarbyl, preferably C10-C14 alkyl, independently p is 1 to about 3 and q is 1 to about 3, R2 is C1-C3 alkyl, preferably methyl, and X is an anion, especially chloride.
Other compounds of the foregoing type include those wherein the ethoxy (CH2CH2O) units (EO) are replaced by butoxy (Bu), isopropoxy [CH(CH3)CH2O] and [CH2CH(CH3O] units (i-Pr) or n-propoxy units (Pr), or mixtures of EO and/or Pr and/or i-Pr units.
Additional cationic surfactants are described, for example, in the xe2x80x9cSurfactant Science Series, Volume 4, Cationic Surfactantsxe2x80x9d or in the xe2x80x9cIndustrial Surfactants Handbookxe2x80x9d. Classes of useful cationic surfactants described in these references include amide quats (i.e., Lexquat AMG and Schercoquat CAS), glycidyl ether quats (i.e., Cyostat 609), hydroxyalkyl quats (i.e., Dehyquart E), alkoxypropyl quats (i.e., Tomah Q-17-2), polypropoxy quats (Emcol CC-9), cyclic alkylammonium compounds (i.e., pyridinium or imidazolinium quats), and/or benzalkonium quats.
High Absorbing Material
The cationic particle of the present invention also contains a water-insoluble high absorbing material. The water-insoluble high absorbing material is a material having an oil absorption (using di-butyl phthalate) of preferably from about 140 mL/100 g to about 400 mL/100 g, even more preferably from about 200 mL/100 g to about 300 mL/100 g.
Preferably, the high absorbing material is selected from the group consisting of aluminosilicate, precipitated silica, amorphous silica, talc, and mixtures thereof.
Especially preferred are sodium aluminosilicates and amorphous precipitated silica. An example of an amorphous precipitated silica is a porous hydrophyllic silica (trademark SIPERNAT 22S) available by DeGussa. Another example of a precipitated silica is a white carbon, such as calcium silicate synthetic amorphous silica, (trademark Carplex) available by Shionogi and Company Ltd.
In a preferred cationic particle, the ratio of the high absorbing material to the cationic surfactant active when forming the particle is from about 1:3 to about 1:1, even more preferably from about 1:2 to about 1:1. Absorption here means that the high absorbing material is coated with the cationic surfactant solution, and/or that the high absorbing material is impregnated with the cationic surfactant solution.
The finished cationic particle preferably has a mean particle size of greater than about 100 microns, and more preferably from about 100 microns to about 1000 microns, even more preferably from about 150 microns to about 650 microns.
A preferred finished cationic particle has the following composition, by weight percent of the cationic particle: cationic surfactant active from about 30% to about 65%; moisture content of from about 3% to about 15%; and the balance, the high absorbing material. Optionally filler and anionic surfactant may be included.
One embodiment for the cationic particle contain in addition, some anionic surfactant. If included, the ratio of anionic surfactant active to cationic surfactant active is from about 1:10 to about 1:30, preferably from about 1:15 to about 1:25. By weight percentage of the finished cationic particle, the content of anionic surfactant is preferably from about 1% to about 5%. Of course, the anionic surfactant may in addition be included as an additional cleaning component for the final detergent composition. Although not wanting to be limited by theory, it is believed that the addition of small quantities of anionic surfactant in the cationic particle provides free flow characteristics to the cationic particle and provides a less sticky surface on the cationic particle.
The cationic particle optionally also contains a filler, such as soda ash, other silicate, and/or sulfate.
Additional Deteraent Composition Components
The cationic particle may be formulated in detergent compositions. Such detergent compositions herein may optionally comprise other known detergent cleaning components including alkoxylated polycarboxylates, bleaching compounds, brighteners, chelating agents, clay soil removal/anti-redeposition agents, dye transfer inhibiting agents, enzymes, enzyme stabilizing systems, fabric softeners, polymeric soil release agents, polymeric dispersing agents, suds suppressors. The detergent composition may also comprise other ingredients including carriers, hydrotropes, processing aids, dyes or pigments. The preferred detergent compositions have a wide range of density, e.g., from about 300 g/l to about 1000 g/l, especially for high dense detergent agglomerates e.g., from about 600 g/l to about 850 g/l.
The cationic particle can be used to formulate detergent compositions. In such detergent compositions, the amount of cationic particle, by weight of the final detergent composition is preferably from about 0.5% to about 30%, more preferably from about 0.5% to about 10%.
Preferred examples of the process of making the cationic particle of the present invention is described below. In one method of making the cationic particle via a spray drying process, the cationic surfactant solution, high absorbing material, and optionally anionic surfactant and a filler, are mixed and agitated to form a substantially homogenous mixture. The mixture is then sprayed into a tower, wherein cationic particles are formed. In another method of making the cationic particle via an agglomeration process, the cationic surfactant solution is added to the high absorbing material and agitated in a mixer to form a moist granular powder, or agglomerate. The powder is then dried, such as in a fluid bed dryer, to form the finished cationic particle.